Questions tagged [ekf]

the extended Kalman filter, a filter for nonlinear state estimation.

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Robot_Localization Local/Global ekf nodes

I have a doubt regarding the use of Robot_localization. I was watching this tutorial: https://navigation.ros.org/tutorials/docs/navigation2_with_gps.html in my case I have a real robot (equipped with ...
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1 answer
35 views

UKF position data closely match slam absolute pose regard wheel odometry

I have a specific question related to a robot localization package. I've been trying to get an answer on the Robot Stack Exchange for quite some time now, but I haven't received a response. I'm ...
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0 answers
43 views

EKF not providing good position estimation

I am working on a robotics project and I am using the package robot_localization in ROS2. I am trying to fuse the wheel odometry and IMU data, but I am struggling a lot to make it work. I've read a ...
2 votes
1 answer
225 views

robot_localization GPS causing large drift/covariance spike

I am trying to implement the dual ekf navsat example on my real-world robot. The local EKF with wheel odometry and IMU works quite well and has no issues. As far as I can tell, my global EKF ...
2 votes
1 answer
274 views

Frequency Limitation in robot_localization's EKF Node

I'm using version 2.7.4 of the robot_localization package for ROS Noetic. I'm currently utilizing two nodes of the package: EKF Local Node: Fuses data from an IMU (100Hz) and wheel encoders (4Hz). ...
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1 answer
145 views

EKF of robot_localization have a delay compared to GPS data

I am using ros2 humble and the extended Kalman Filter from the robot_localization package to get both the odom -> base_link and ...
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2 answers
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seeking clarity regarding the 'world_frame' parameter in ekf_localization node

I have spawned two husky bots (namespaced husky_1 and husky_2) in the Gazebo world. I am ...
0 votes
1 answer
58 views

Diff-drive robot estimation sliding sideways with robot-localization

I'm trying to configure an ekf_filter_node. I started by adding just the odom topic from a ros2_control DiffDriveController in gazebo. For some reason, the robot starts sliding sideways in odom (in ...
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2 answers
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Not accurate results of yaw when fusing wheel encoders with imu using robot_localization

Hello, I have differential drive Jaguar 4x4 wheel mobile robot. I am trying to fuse wheel odometry data with IMU sensor measurements using robot_localization. The problem is that after some time (...
4 votes
2 answers
2k views

the uncertainty of initializing new landmark in EKF-SLAM

In EKF-SLAM (based-feature map) once the robot senses a new landmark, it is augmented to state vector. As a result, the size of the state vector and the covariance matrix are expanded. My question is ...
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robot_localization package position output is the same as input absolute pose

Hello my question is whether this type of output is a proper output? I fuse absolute pose from slam and fuse linear velocity from wheel odometry, but the filter output position data is the same as the ...
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29 views

Robot Localization pkg / Motion Model prediction step

As I was investigating the transition functions in the prediction step in the ROS Robot Localization pkg (ekf.cpp) . I found for the orientation equations there are as follows: Roll angle is the ...
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25 views

EKFSLAM with LiDAR and IMU + GPS localization module

There are many resources that relate to EKFSLAM based on the presence of only a LiDAR unit, which localize both the vehicle and the detected landmarks. I see that they often use state vectors that get ...
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1 answer
70 views

navsat_transform node doesn't publish utm_transform

Hi, please, help me with following issue, i've been trying to solve it for a week already... Can't make my navsat_transform node publishing utm_transform. And odometry/filtered from EKF always has ...
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1 answer
6 views

What is the purpose of splitting SLAM odom and EKF odom frames in waypoint_nav?

I have a robot somewhat similar to the clearpath husky . In their gmapping launch file, they have their odom frame set to 'odom_gmapping'. config shown here: ...
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1 answer
83 views

[Robot Localization] How to use absolute orientation from IMU with absolut positionning from visual SLAM

Hi, I'm quite new to ROS and robot_localization so I'm getting confused really fast with TFs. I've been using for some time now a visual SLAM algorithm that works fine and I'd like to slowly improve ...
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2 answers
137 views

Odometry into EKF for localization

I want to fuse a Lidar-Odometry into my EKF where I'm already using encoder, IMU, GPS. The odometry has as output a delta pose, how to put that into the filter? How to deal with the covariances?
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157 views

MPU6050 providing gyroscope values for linear acceleration

I am using this ROS2 driver to connect my MPU6050 to RPi 4 running ROS2 humble. It outputs an IMU message containing linear acceleration and angular velocity. The linear acceleration values seem to be ...
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1 answer
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Issue in using IMU MPU 6050

Hello, I have been trying to implement MPU 6050 imu sensor using, MPU SERIAL NODE , when i initially run the node, IMU values seem fine, for example, linear accelerations in x, y, z directions come to ...
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168 views

Extended Kalman Filter Robot Localization Drift

I have implemented an EKF for robot localization in the style of robot_localization using the famous C++ template kalman library....
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74 views

Nonlinear continuous system function of IMU sensor fusion robot

For my robotics course I have to implement the nonlinear continuous system function for a mobile robot that is equipped with a GPS receiver and an IMU consisting of an accelerometer and a gyroscope. ...
0 votes
1 answer
8 views

Jiggling tf Tree After fusing Odometry with IMU

I am using ROS NOETIC and Pioneer3DX as the mobile robot which publishes Odometry info into /RosAria/pose topic as nav_msgs/Odometry message. Phidgets Spatial IMU is being used which published the IMU ...
2 votes
1 answer
67 views

Confused with EKF Localization

I have been trying to understand EKF localization from Probabilistic Robotics by Thrun Burgard and Fox. There the covariance prediction is given by $$\overline{\Sigma }_t=G_t\Sigma_{t-1}G^T_t+V_tM_{t-...
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1 answer
75 views

what exactly is 'observation model' for a robot

In my journey to understand the Kalman filter, I understood how a state model representation is derived for a robot and why(to get the robot state for a given input u) it is required. $$ \boldsymbol{...
1 vote
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667 views

robot_pose_ekf won't publish any messages

I am having trouble getting the robot_pose_ekf package to publish messages. I launch it with this launch file. ...
2 votes
0 answers
50 views

Why is the EKF approximated this way?

I'm a student that recently started taking a course on cognitive robotics. The book I use is Probabilistic Robotics by Thrun Burgard and Fox. In the EKF algorithm, we linearized the action model in ...
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1 answer
151 views

Extended Kalman Filter and PID controller

I'm trying to build a model based on tracking an object in 2-D using MATLAB (time-varying system). I built the model using an Extended Kalman Filter and a PID controller. I have a doubt regards the ...
0 votes
1 answer
55 views

Robot_localization ekf node does not subscribe to Odom topic

Hello, I am trying to fuse my odometry from my 2D differential drive robot, with my imu using the ekf from RL. The odometry works fine on it's own, but I think I must be missing something simple in my ...
1 vote
1 answer
1k views

EKF implementation on odometry/IMU

I am applying Extended Kalman Filter for a mobile robot with IMU and odometry data. I am running simulation currently. However, I don't have suitable data for odo/IMU measurements to use. Where can I ...
2 votes
1 answer
183 views

Doubt with linearization and discretization process - Ekf

In the paper "State Estimation for Legged Robots - Consistent Fusion of Leg Kinematics and IMU", the authors describe the application of an extended kalman filter to estimate states of a quadruped ...
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1 answer
23 views

IMU sensor coordinates for EKF

Hi, I am using ekf to fuse multiple IMU. I was reading this portion ...
6 votes
1 answer
551 views

How do you determine EKF process noise for pre-recorded data sets?

I've seen this question, which asks about determining the process noise for an EKF. I don't see anything there about pre-recorded data sets. My thought on how to determine the noise parameters, ...
0 votes
1 answer
102 views

Derivation of EKF slam landmark initialization

I have read a couple posts which gives the formula for initializing a new landmark in EKF slam but the derivation is not given. EKF-SLAM initialize new landmark in covariance matrix Could someone ...
1 vote
0 answers
644 views

robot_localization not fusing imu data

According to the documentation in : http://docs.ros.org/en/noetic/api/robot_localization/html/state_estimation_nodes.html I was able to transform the imu data header fram from "imu_link" ...
1 vote
1 answer
246 views

EKF slam vs global bundle adjustment

How does EKF slam and the covariance matrix interact with global bundle adjustment? In particular the covariance matrix gives you a confidence on location but global bundle adjustment does not. How do ...
1 vote
1 answer
2k views

robot_localization EKF node does not publish on /odometry/filtered (ROS2 Foxy)

I am using ROS2 Foxy and Gazebo 11 in Ubuntu 20.04. I have a URDF description of a mobile robot that uses 4 wheels for mecanum drive. Using the robot_localization package, I am creating an EKF node ...
2 votes
1 answer
466 views

Why innovation equation in Extended Kalman filter is called innovation?

In the Extended Kalman filter for SLAM, why is the innovation equation called so? Is there a reason for using the specific word "innovation" for the difference between the observed ...
1 vote
1 answer
154 views

EKF SLAM Prediction Step

My question relates to the prediction step in EKF SLAM when we get measurements. This is a question I've encountered while implementing EKF SLAM in ROS. At the beginning of the SLAM loop, we predict ...
0 votes
1 answer
416 views

Estimate noise covariance matrix of measurements using a ros-bag

I am facing the following issue, and some hint or orientation would be great. I am working on a project in which I was given a ROS bag, and I have to implement a localization node using SLAM. To do so,...
0 votes
1 answer
44 views

how to use IMU sensor with relative orientation data in navsat transform node

Hi, I am working on fusing visual odometry, IMU, and gps sensor by using a robot localization package. There are a couple of issues with my IMU data 1) it's not giving absolute orientation or heading ...
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3 answers
2k views

Do I need a camera along with LIDAR for SLAM?

Equipment: Pi 3 B Mega 2x Encoder Motor 12VDC 299RPM MPU 6050 12V bat 2000mAh LIDAR or Kinect ? I want to implement EKF SLAM. I have referred bot NOX ROS wandering robot, Hussarian CORE and Robotics ...
0 votes
1 answer
392 views

Derive the system's dynamics function and the Jacobian Matrix G of Extended Kalman Filter of a differential drive robot on a 2D plane

I have found the following answer on the system's dynamics function and what the Jacobian matrix G of the Extended Kalman Filter look like for a 2D robot with a differential drive. Taken from slides ...
0 votes
1 answer
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navsat_transform_node geographicErr

Hello, I am usinf the robot_localization_package to localize a differential drive robot. In my setup, I follow the guidelines of the package documentation about fusing the GPS with dead reckoning and ...
0 votes
1 answer
4 views

EKF start to predict after amcl stop sending pose

Hello, I'm trying to use robot_localization to fuse amcl_pose with encoder odom, and latter GPS. The experiment is basing on Turtlebot3, gazebo and ros2-foxy. It's working well if the robot is moving. ...
2 votes
2 answers
423 views

Tracking vehicle 6 states extended kalman filter required?

I'm trying to track an accelerating vehicle using a camera, an IMU, and a GPS. I use for the state space equation a constant acceleration model: The states are the position, the velocity, and the ...
3 votes
1 answer
612 views

What's the correct approach to merging of localization and odometry data?

We've got a mobile platform with a source of odometry and an IMU, which are merged in an EKF filter (robot_localization node), producing continuous odom->base_link transform. The robot is also ...
0 votes
1 answer
175 views

Usage of Falkolib(OpenSLAM) for 2D lidar landmark extraction

I am using Falkolib for landmark extraction in a 2D environment. Currently I am using the testKeypointOC executable from the bin directory. I have changed the testKeypointOC.cpp file and the ...
0 votes
1 answer
5 views

robot_localization (ekf node) output is not stable for a long time

Hi. I am using ekf_localization_node for fusing imu, wheel odometry and amcl_pose ( My config is as follow ) The reason why i am using amcl_pose; When i use ...
1 vote
1 answer
323 views

No difference between UKF and EKF for SLAM

I built EKF and UKF SLAM algorithms. The problem is that I expected to see a difference because of the more precise approximation of the system in the UKF. Here's a screenshot from the estimated path ...
0 votes
1 answer
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robot_localization IMU yaw velocity causes vertical drift

Hi, I am using robot_localization's EKF node with my robot's wheel odometry and an IMU. My configuration file is the following: ...

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